1. Technical Field
The present invention relates to a flexible protective guide for internally holding long flexible cables and/or ducts and guiding their behaviors to a given path, while protecting the cables and/or ducts, the cables and/or ducts connecting a fixed side of a machine in which the protective guide is installed to a movable side of the machine to transmit electrical signals therebetween or transfer a physical medium therebetween. In particular, the present invention relates to a long flexible protective guide preferable for an application in which cables and/or ducts are bent for connection between a fixed side of a machine in which the protective guide is installed and a movable side of the machine.
2. Related Art
It is well known that various machines available today are provided with a movable member, such as a linear actuator or a robot, which is connected, for actuation, to a member on a fixed side (hereinafter referred to as a fixed member) of the machine. In most of such machines, energy, such as electrical power, control signals and/or air, are required to be transferred to the movable member from the fixed member via cables and/or ducts (hereinafter just referred to as cables). Since the cables are connected between the fixed member and the movable member, it is important to guide the movement of the cables to a desired path, with the protection of the cables.
As a means for protecting and guiding such cables, a protective guide chain as disclosed in JP-A-H10-047441 is well known. The protective guide chain includes a number of link members connected in the longitudinal direction of cables. Each link member is composed of a pair of left and right link plates which are spaced apart from each other, a flap and a bottom plate. The flap is used for connecting between the upper edges of the link plates. The bottom plate is used for connecting between the lower edges of the link plates. The movement stroke for which the chain is used is different between the users, and thus ranges from a short movement stroke to a long movement stroke. Sometimes, a long chain is required to be used for a movement stroke of 10 meters or more. Taking this into account, the protective guide chain disclosed in JP-A-H10-047441 achieves a required movement stroke by assembling the required number of link members and elongating the chain to the required length.
However, in exchange of the possible elongation by assembling the link plates, such an assembled protective guide chain involves lots of work in assembling the link plates, the flaps and the bottom plates. Further, when such an assembled protective guide chain is used, dust may be produced due to the friction between the link plates. In addition, when such an assembled protective guide chain is bent, noise may be mutually caused by the link plates. Also, such an assembled protective guide chain may cause vibration due to the mutual polygonal action of the link plates.
In order to take measures against these problems, JP-A-2001-514725 suggests a cable protective member. The protective member is configured by segments each of which is formed by injection-molding a synthetic resin into a flat one-piece structure. These segments are mutually connected via bendable bridges so that the protective member is foldable. Accordingly, it is no longer necessary to connect adjacent link plates and thus the assembling works are dramatically facilitated. Also, the protective member of JP-A-2001-514725 reduces production of dust, generation of noise due to bending, and vibration due to polygonal action, which are the problems of the protective guide chain disclosed in JP-A-H10-047441.
However, in the foldable cable protective member of JP-A-2001-514725, each segment is provided by injection-molding a synthetic resin into a one-piece flat structure. Therefore, the foldable cable protective member, when it is applied such as to a linear actuator machine having a long movement stroke, is very often difficult to be manufactured with the length suitable for the long movement stroke. For example, there is a physical limitation in the size of the die used for injection molding. Further, since a desired movement stroke is different between the users, providing a plurality of dies suitable for the individual desired movement strokes invites increase in the manufacturing cost.